The present invention relates to an apparatus and a method for semiconductor, and more particularly, to an apparatus and a method for depositing particles onto a wafer used for measuring a reliability of an apparatus for examining particle contamination on a wafer.
In manufacturing a semiconductor, inspection processes should be carried out on many items in order to manufacture a final good die. Of many items to be inspected, particles contaminating wafers are principle factor causing electrical open or short at the moment the particles are deposited on the substrate of the semiconductor circuit. For this reason, the processes for inspecting and analyzing the particles are the most important of the every process for manufacturing the semiconductor. That is, it is important to inspect and analyze the particles on a wafer by using the particle inspection and analysis system, thereby preventing contamination of the device by the particles.
Currently, the particles inspection and analysis system (e.g. wafer surface scanner and scanning electron microscope) is applied to a wafer on which the particles of known kind, size and number are deposited to investigate the size and numbers of the particles. When the investigation results are same as the known size and number, the system is considered to have accuracy.
In conventional method, the wafer, on which the polystyrene latex is deposited, is frequently used as a wafer available for measuring the accuracy of the particles inspection and analysis system. And the wafer, on which the polystyrene latex of an uniform size is deposited, is commercially available from VLSI, or manufactured by using the wafer spinner.
FIG. 1 is a diagram roughly showing a conventional apparatus for depositing particles onto a wafer.
The conventional apparatus for depositing particles onto a wafer comprises: an atomizer generating the polystyrene latex; a dryer for drying the polystyrene latex; a differential mobility analyzer (hereinafter, referred to as DMA) discharging only the polystyrene latex of an uniform size after classifying the polystyrene latex by sizes; an impactor passing though only the polystyrene latex of a small size among the discharged polystyrene latex from the DMA; a chamber in which a tube for depositing the polystyrene latex from the impactor onto the wafer is installed; and a counter for counting the number of the lost polystyrene latex not deposited.
The size of the polystyrene latex deposited onto the wafer is controlled by using the DMA.
However, there are disadvantages as follows.
First, the polystyrene latex can be guaranteed for its size due to an uniform size distribution. However it is very difficult to investigate the number of the deposited particles. Therefore, it is difficult to measure the accuracy of the particle inspection and analysis system because, though, the size of the particles can be controlled, the number thereof can not.
Second, many different wafers must be prepared depending on desired particles' kind and size because only the particles of same kind and size can be deposited onto a wafer.
Third, it is difficult to obtain the particles of an uniform size when, besides polystyrene latex, other particles generated during the manufacturing process of the semiconductor are applied to the conventional apparatus.